@Peter10 If I were you, and it's physically possible for you (you live nearby) I would leave enough towels and linen for a week, and arrange a pick-up of dirty stuff and delivery of clean, once a week.
If you let guests wash these things, you are likely to find things stained beyond redemption. Many stains need to be pretreated, soaked in cold water, etc, to come out. If guests just throw things in a hot wash, the stains will be cooked in, never to be usable again for future guests.
I don't do long term, but I give guests 2 bath towels, a hand towel, and a washcloth, for 5 days-week. So I would say 3 bath towels, 2 hand towels and 2 wash cloths per week, would be sufficient, with a weekly exchange of dirty for clean.